/ Abstract Spray-on polyurethane coatings applied during auto body repair expose workers to potentially harmful levels of diisocyanates. Workers also commonly risk exposure to harmful vapors during the manufacture of molded polyurethane foam products. Diisocyanates have been identified as the major cause of occupational asthma. LightLine Technologies proposes to develop a highly sensitive fiberoptic personal monitoring device, similar to a sampling badge, targeted for the simple and convenient measurement of diisocyanate airborne exposure. A chemically reactive coating applied to the fiber will provide a direct integrated response to all diisocyanate vapors during exposure. This compact, battery powered device will monitor exposure in real-time and provide rapid, low cost, feedback to the user of unhealthy exposure levels that are recorded and reported via digital electronics. Humidity and temperature compensation will be integrated into the device so as to make exposure measurement more accurate. An explicit program goal is to make the device size and cost suitable for consistent use during typical auto body repairs and factory operation. A differentiating version of the fiber sensor will provide for a separate measurement of aromatic diisocyanate exposures. Diisocyanates are highly toxic, used worldwide, and produced on a very large scale for the production of polyurethane and related chemical products. Since most human exposure occurs as the chemical vapors are transported by air, an air sampling based method having high sensitivity is required. Current measurement methods fail to provide adequate sensing of all diisocyanate species simultaneously. The anticipated results of the SBIR program will be to: 1) Determine an optical fiber based sensor fabrication process, use procedure, and real-time readout process that provides high sensitivity and high confidence evaluation of diisocyanate vapor species in air. 2) Design, build and test a prototype personal exposure sensor and readout package that accurately provides sensing capabilities for human exposure determination in industrial environments. [unreadable] [unreadable] [unreadable] [unreadable]